Signal processing generally has the purpose of extracting information from a given signal by analysis and processing. Although a variety of signal types need to be processed, they have one thing in common, namely that they are subject to noise due to different phenomena. It is generally advantageous to control the signal processing such that the highest dynamic range possible or a high signal-to-noise ratio can be achieved. In this context, the dynamic range DR is respectively defined as the ratio between the maximal signal Smax and the noise component N or
  DR  =                    S        max            N        .  
FIG. 6 shows an exemplary signal processing path with several stages ST1, ST2 that respectively may represent elements such as amplifiers, buffers, analog-digital converters and the like, or comprise one or more of these elements. Signal processing by the stages ST1, ST2 usually takes place serially and in series, respectively.
Noise Nst1, Nst2 is respectively impressed on the signal Sin to be processed or the intermediate signals derived thereof by each of the individual stages ST1, ST2. An original input signal Sin is thus converted into an output signal Sout, on which an overall noise Nout is superimposed:Sin→Sout+Nout.
A simple observation in this model shows that further noise is added into the signal processing with each additional processing stage. To this end, respective noise sources Nst1, Nst2 that are added to the signal Sin in each processing stage ST1, ST2 are shown in FIG. 6. In that model, each of the processing stages ST1, ST2 is furthermore represented by a characteristic amplification factor A1, A2. The output signal Sout then results from the signal Sin as a function of the amplification factors A1, A2 in the form ofSout=Sin·A12·A22.On the other hand, the noise is also amplified and, therefore, results in an overall noise NoutNout=Nst1·A12·A22+Nst2·A22.
To respectively ensure the best signal-to-noise ratio possible or a high dynamic range DR, it is advantageous to increase the signal amplitude with amplification factor A1 as early as possible in the signal processing chain ST1, ST2 because:
      N    in    =                    N        out                    (                              A            1            2                    ·                      A            2            2                          )              =                  N                  st          ⁢                                          ⁢          1                    +                                    N                          st              ⁢                                                          ⁢              2                                            A            1            2                          .            applies to the input noise Nin.
Theoretically, it would therefore be advantageous to already amplify signals to infinite amplitude in the first stage ST1 such that subsequent noise with arbitrary, but finite intensity no longer influences the dynamic range DR.
In practical applications, the signal amplitude naturally cannot be arbitrarily increased and the maximum of a signal depends on the corresponding transmission medium such as a voltage, current or the like. If the signal processing is carried out, for example, by a voltage, the maximal signal is usually limited by the minimal supply voltage of the circuit. The intensity of the minimal supply voltage usually cannot be additionally increased during processing in this case.
It could therefore be helpful to provide a signal processing arrangement and a signal processing method that make it possible to achieve a high dynamic range with simple means.